1. Field of the Invention
The invention relates to a test rig for internal combustion engines which includes a pedestal upon which is arranged the internal combustion engine that is to be tested, on the one hand, and at least one rotationally connected driving engine or load generator, on the other hand, that is arranged opposite to the former on the output side.
2. The Prior Art
Test rigs of the type referred to above allow via the presetting of certain engine speed and/or torque processes of the driving engine or load generator for the simulation of the influence and/or retroactive effect of the ambient operational conditions on the output of the combustion engine that is to be tested. This is of great advantage particularly, for example, during the development phase of a combustion engine when the vehicle that is to be powered by the engine, including all of the components of the power train, does not yet exist in reality because, via the already very highly dynamically controllable driving engine or load generators, it is nowadays possible to thereby achieve nevertheless advance simulations that are very close to the reality of the later actual conditions of use.
In the context of known test rigs of the type referred to above problems always arise with regard to the space that is available on the pedestal if the testing is to be done using the mounted original exhaust system, for example, in order to test a piston internal combustion engine with several serially arranged cylinders that is to be installed with the crankshaft in the longitudinal direction of the vehicle, whereby it normally has an exhaust system that extends underneath the crankshaft axis essentially toward the back in the longitudinal direction of the vehicle. More and more frequently, this is the desired option in order to test as closely to reality as possible. In this instance, the exhaust pipes and possibly also catalytic converters and mufflers come to lie in relation to the pedestal at the location where, normally, otherwise the driving engine or load generator is arranged on the pedestal. This is why for known apparatuses to date the driving engine or load generators for such test rigs are most of the time mounted on a support frame with an open bottom on the pedestal; this, however, requires the arrangement of a transmission, a belt drive, etc., that bridges the correspondingly emerging axial displacement between combustion engine output and/or driving engine or load generator.
Also known in the art are solutions that provide for the driving engine or load generator to be connected via a bevel gear system causing the driving engine or load generator to be arranged as perpendicular next to the internal combustion engine. Furthermore, also known in the art is the use of a correspondingly long connecting shaft (often the original cardan shaft) between internal combustion engine and driving engine or load generator. In all cases, additional inertias, elasticities, tooth play etc. result in negative effects, in particular during highly dynamic operation, as well as in additional service and installation complexities and, specifically for transmission solutions, elevated noise levels at the test rig.
The object of the present invention consists therefore in providing test rigs of the type outlined in the introduction, in particular, in such a way that they can easily be used also for testing internal combustion engines with mounted original exhaust systems that substantially lead away from the internal combustion engine beneath the input axle parallel to the extension thereof without the disadvantages that afflict the known solutions.